1. Field of Invention
The present invention relates to a liquid crystal display device. More particularly, the present invention relates to a pixel structure and its driving method of a liquid crystal display device.
2. Description of Related Art
During driving a liquid crystal display device, a driving voltage cannot be fixed at a voltage value, otherwise characteristics of crystal molecules might be damaged by a long-period driving. Therefore, every now and then, the driving voltage must be altered to avoid such damages upon the crystal molecules.
In order to solve this issue, driving phases for the liquid crystal display device are divided into two types: positive polarity and negative polarity. When a pixel electrode is supplied with a higher voltage than a common electrode is supplied with, the pixel is positively polarized. When a pixel electrode is supplied with a lower voltage than a common electrode is supplied with, the pixel is negatively polarized. When a voltage difference between the pixel electrode and the common electrode is the same, the same grayness would be presented by the pixel.
Several conventional polarity inversions between positive polarity and negative polarity are listed as follows: frame inversion, row inversion, column inversion and dot inversion.
When a frame refreshes, flickers are generated by the liquid crystal display device and make human eyes uncomfortable. The flickers are most-frequently generated when the frame inversion is applied in the liquid crystal display device. Other inversion ways may produce the flickers, but not as frequent as the frame inversion does.
Another issue of the liquid crystal display device is “cross talk”, which means adjacent pixels interfere with each other, thereby displaying incorrect information. Dot inversion is the best way to reduce cross talk, but also consumes more power than the other inversion ways. How to reduce “cross talk”, “flicker” and consume less power in a liquid crystal display device is an urgent issue for those persons skilled in the art.
For the forgoing reasons, there is a need for an improved pixel structure and its driving method of a liquid crystal display device.